U.S. patent application number 16/462479 was filed with the patent office on 2019-09-05 for polymeric multilayer film with openings.
The applicant listed for this patent is 3M INNOVATIVE PROPERTIES COMPANY. Invention is credited to Garth V. Antila, Graham M. Clarke, Jeffrey O. Emslander, Brent R. Hansen, John J. Rogers, David F. Slama, Jacob D. Young.
Application Number | 20190270271 16/462479 |
Document ID | / |
Family ID | 60543687 |
Filed Date | 2019-09-05 |
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United States Patent
Application |
20190270271 |
Kind Code |
A1 |
Slama; David F. ; et
al. |
September 5, 2019 |
POLYMERIC MULTILAYER FILM WITH OPENINGS
Abstract
Polymeric multilayer films having an array of openings extending
between the first and second major surfaces of the film, and a
thickness greater than 50 micrometers, wherein the openings each
have a series of areas through the openings from the first and
second major surfaces ranging from minimum to maximum areas, and
wherein the minimum area is not at at least one of the major
surfaces. Polymeric multilayer films described herein are useful,
for example, for wound dressings and graphics films.
Inventors: |
Slama; David F.; (City of
Grant, MN) ; Antila; Garth V.; (Hudson, WI) ;
Hansen; Brent R.; (New Richmond, WI) ; Clarke; Graham
M.; (Woodbury, MN) ; Emslander; Jeffrey O.;
(City of Grant, MN) ; Rogers; John J.; (St. Paul,
MN) ; Young; Jacob D.; (St. Paul, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
3M INNOVATIVE PROPERTIES COMPANY |
St. Paul |
MN |
US |
|
|
Family ID: |
60543687 |
Appl. No.: |
16/462479 |
Filed: |
November 8, 2017 |
PCT Filed: |
November 8, 2017 |
PCT NO: |
PCT/US2017/060544 |
371 Date: |
May 20, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62427887 |
Nov 30, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B32B 2367/00 20130101;
B29C 48/16 20190201; B32B 37/153 20130101; B32B 27/283 20130101;
B32B 37/0053 20130101; B32B 2250/44 20130101; B32B 25/042 20130101;
B32B 2323/00 20130101; B32B 2405/00 20130101; B32B 7/12 20130101;
B32B 2250/03 20130101; B32B 25/16 20130101; B32B 27/08 20130101;
B32B 2535/00 20130101; B32B 3/30 20130101; B32B 27/34 20130101;
B32B 25/08 20130101; B32B 2255/10 20130101; B32B 27/306 20130101;
B32B 38/10 20130101; B32B 23/20 20130101; B32B 38/06 20130101; B32B
7/06 20130101; B32B 27/32 20130101; B32B 25/12 20130101; B32B 25/14
20130101; B32B 27/36 20130101; B32B 2307/732 20130101; B32B 3/266
20130101; B32B 2250/24 20130101; B32B 3/263 20130101; B32B 2325/00
20130101; B32B 27/302 20130101; B32B 27/365 20130101; B32B 27/308
20130101; B32B 2250/04 20130101; B32B 2255/26 20130101; B32B
2451/00 20130101 |
International
Class: |
B32B 3/30 20060101
B32B003/30; B32B 3/26 20060101 B32B003/26; B32B 7/12 20060101
B32B007/12; B32B 7/06 20060101 B32B007/06; B32B 27/32 20060101
B32B027/32; B32B 27/30 20060101 B32B027/30; B32B 27/36 20060101
B32B027/36; B32B 27/08 20060101 B32B027/08; B32B 38/10 20060101
B32B038/10; B32B 37/15 20060101 B32B037/15 |
Claims
1. A polymeric multilayer film having first and second generally
opposed major surfaces, the polymeric film comprising in order: a
layer comprising a pressure sensitive adhesive, optionally a tie
layer, and a layer comprising a thermoplastic polymer, an array of
openings extending between the first and second major surfaces, and
a thickness greater than 50 micrometers, wherein the openings each
have a series of areas through the openings from the first and
second major surfaces ranging from minimum to maximum areas, and
wherein the minimum area is not at at least one of the major
surfaces.
2. The polymeric multilayer film of claim 1, wherein the openings
have a largest dimension of at least 50 micrometers.
3. The polymeric multilayer film of claim 1, wherein the openings
have a largest dimension in a range from 50 micrometers to 1000
micrometers.
4. The polymeric multilayer film of claim 1 that includes the tie
layer.
5. The polymeric multilayer film of claim 4, wherein the tie layer
comprises at least one of an ethylene methyl acrylate copolymer,
ethylene acrylic acid copolymer, ethylene butyl acrylate copolymer,
ethylene vinyl acetate, ethylene acid terpolymer, polybutene, or
polymethylpentene.
6. The polymeric multilayer film of claim 1, wherein the pressure
sensitive adhesive comprises at least one of a natural rubber, a
synthetic rubber, a styrene block copolymer, a polyvinyl ether, an
acrylic, a poly-a-olefin, a silicone, or an acrylate.
7. The polymeric multilayer film of claim 1, wherein the
thermoplastic polymer is at least one of polyamide 6, polyamide 66,
polyethylene terephthalate, copolyester, cellulose acetobutyrate,
30 polymethylmethacrylate, acrylonitrile butadiene styrene,
polyolefin copolymers, polyethylene, and polystyrene, ethylene
vinyl alcohol, polycarbonate, polybutyleneterephthalate,
polyethylenenaphthalate, or polypropylene.
8. An article comprising the polymeric multilayer film of claim 1
and a liner layer adjacent the layer comprising pressure sensitive
adhesive, such that the order of the layer is: the liner layer, the
layer comprising pressure sensitive adhesive, optionally the tie
layer, and the layer comprising thermoplastic polymer.
9. A method of making a polymeric multilayer film, the method
comprising: extruding at least the layer comprising pressure
sensitive adhesive, optionally the tie layer, and the layer
comprising thermoplastic polymer into a nip along with a liner
layer to provide a polymeric multilayer film with a liner layer,
wherein the nip comprises a first roll having a structured surface
that imparts indentations through a first major surface of the
polymeric multilayer film; removing the liner; and passing the
first major surface having the indentations over a chill roll while
applying a heat source to a generally opposed second major surface
of the polymeric multilayer film, wherein the application of heat
from the heat source results in formation of openings to provide
the polymeric multilayer film of claim 8.
10. A polymeric multilayer film having first and second generally
opposed major surfaces, the polymeric film comprising in order: a
backing layer comprising a first thermoplastic polymer, a layer
comprising a pressure sensitive adhesive, optionally a tie layer,
and a strippable layer comprising a second thermoplastic polymer,
an array of openings extending between the first and second major
surfaces, and a thickness greater than 50 micrometers, wherein the
openings each have a series of areas through the openings from the
first and second major surfaces ranging from minimum to maximum
areas, wherein the minimum area is not at at least one of the major
surfaces, wherein the polymeric layer is immiscible with the
pressure sensitive adhesive, and wherein the strippable layer is
removable from the layer comprising pressure sensitive adhesive at
a peel force less than 200 grams per cm as determined by the Peel
Test described in the Examples.
11. The polymeric multilayer film of claim 10, wherein the openings
have a largest dimension of at least 50 micrometers.
12. The polymeric multilayer film of claim 10, wherein the openings
have a largest dimension in a range from 50 micrometers to 1000
micrometers.
13. The polymeric multilayer film of claim 9 that includes the tie
layer.
14. A method of making a polymeric multilayer film, the method
comprising: extruding at least the backing layer comprising the
first thermoplastic polymer, the layer comprising pressure
sensitive adhesive, optionally the tie layer, and the strippable
layer comprising the second thermoplastic polymer into a nip to
provide a polymeric multilayer film, wherein the nip comprises a
first roll having a structured surface that imparts indentations
through a first major surface of the polymeric multilayer film; and
passing the first major surface having the indentations over a
chill roll while applying a heat source to a generally opposed
second major surface of the polymeric multilayer film, wherein the
application of heat from the heat source results in formation of
openings to provide the polymeric multilayer film of claim 10.
15. The method of claim 14 further comprising removing the
strippable layer from the other extruded layers.
16. The method of claim 14 further comprising removing the
strippable layer from the other extruded layers before passing the
first major surface having the indentations, over a chill roll.
Description
BACKGROUND
[0001] Films with openings and pressure sensitive adhesive coatings
are known in the art. Uses for such films include graphic films
adhered with the pressure sensitive adhesive to windows of
buildings, vehicles, etc. For some embodiments of such films (e.g.,
tapes for medical applications and/or adherence to glass widows of
buildings and vehicles) allow moisture from the skin to evaporate
though the film. Perforated films for these applications are
typically less than 150 micrometers (0.006 inch) thick and are
made, for example, of olefin blends or polyvinylchloride.
[0002] Conventional methods for making films with openings include
vacuum or pressurized fluid forming, laser processing, needle
punching, and mechanical punching. These can be characterized into
processes that either displace or remove material in order to form
the opening.
[0003] For applications that require an adhesive layer as part of
the product construction, the adhesive is typically applied to a
substrate before the opening is created, either as a separate
coating step or through the lamination of an adhesive coated liner.
Processes creating openings that displace material can lead to
undesirable issues such as adhesive build-up on the perforating
equipment, additional thickness to perforate, and the possibility
that the adhesive that is displaced during the perforation process
reflows and closing up the perforations over time.
[0004] One method of applying adhesive to the film openings is to
spray the adhesive in a random covering of narrow strands. With
this method, however, the coverage of adhesive is not continuous
and not visually acceptable if adhered to a transparent
surface.
[0005] Additional film constructions with openings and pressure
sensitive adhesive are desired.
SUMMARY
[0006] In one aspect, the present disclosure provides a first
polymeric multilayer film having first and second generally opposed
major surfaces, the polymeric film comprising in order: [0007] a
layer comprising a pressure sensitive adhesive, [0008] optionally a
tie layer, and [0009] a layer comprising a thermoplastic polymer,
an array of openings extending between the first and second major
surfaces, and a thickness greater than 50 micrometers (in some
embodiments, greater than 75 micrometers, 100 micrometers, 125
micrometers, 150 micrometers, 200 micrometers, 250 micrometers, 500
micrometers, 750 micrometers, 1000 micrometers, 1500 micrometers,
2000 micrometers, or even at least 2500 micrometers; in some
embodiments, in a range from 50 micrometers to 1500 micrometers,
125 micrometers to 1500 micrometers, or even 125 micrometers to
2500 micrometers), wherein there are at least 30 openings/cm.sup.2
(in some embodiments, at least 50 openings/cm.sup.2, 75
openings/cm.sup.2, 100 openings/cm.sup.2, 200 openings/cm.sup.2,
250 openings/cm.sup.2, 300 openings/cm.sup.2, 400
openings/cm.sup.2, 500 openings/cm.sup.2, 600 openings/cm.sup.2,
700 openings/cm.sup.2, 750 openings/cm.sup.2, 800
openings/cm.sup.2, 900 openings/cm.sup.2, 1000 openings/cm.sup.2,
2000 openings/cm.sup.2, 3000 openings/cm.sup.2, or even least 4000
openings/cm.sup.2; in some embodiments, in a range from 30
openings/cm.sup.2 to 200 openings/cm.sup.2, 200 openings/cm.sup.2
to 500 openings/cm.sup.2, or even 500 openings/cm.sup.2 to 4000
openings/cm.sup.2), wherein the openings each have a series of
areas through the openings from the first and second major surfaces
ranging from minimum to maximum areas, and wherein the minimum area
is not at at least one of the major surfaces. In some embodiments,
a liner layer is adjacent to the layer comprising pressure
sensitive adhesive.
[0010] In another aspect, the present disclosure provides a method
of making the polymeric multilayer film having a liner layer, the
method comprising:
[0011] extruding at least the layer comprising pressure sensitive
adhesive, optionally the tie layer, and the layer comprising
thermoplastic polymer into a nip along with a liner layer to
provide a polymeric multilayer film with a liner layer, wherein the
nip comprises a first roll having a structured surface that imparts
indentations through a first major surface of the polymeric
multilayer film;
[0012] removing the liner; and
[0013] passing the first major surface having the indentations over
a chill roll while applying a heat source to a generally opposed
second major surface of the polymeric multilayer film, wherein the
application of heat from the heat source results in formation of
openings to provide the polymeric multilayer film with the liner
layer. In some embodiments, the liner layer is subsequently
separated from the extruded layers.
[0014] In another aspect, the present disclosure provides a second
polymeric multilayer film having first and second generally opposed
major surfaces, the polymeric film comprising in order:
[0015] a backing layer comprising a first thermoplastic
polymer,
[0016] a layer comprising a pressure sensitive adhesive,
[0017] optionally a tie layer, and
[0018] a strippable layer comprising a second (in some embodiments,
different) thermoplastic polymer,
[0019] an array of openings extending between the first and second
major surfaces, and a thickness greater than 50 micrometers (in
some embodiments, greater than 75 micrometers, 100 micrometers, 125
micrometers, 150 micrometers, 200 micrometers, 250 micrometers, 500
micrometers, 750 micrometers, 1000 micrometers, 1500 micrometers,
2000 micrometers, or even at least 2500 micrometers; in some
embodiments, in a range from 50 micrometers to 1500 micrometers,
125 micrometers to 1500 micrometers, or even 125 micrometers to
2500 micrometers), wherein there are at least 30 openings/cm.sup.2
(in some embodiments, at least 50 openings/cm.sup.2, 75
openings/cm.sup.2, 100 openings/cm.sup.2, 200 openings/cm.sup.2,
250 openings/cm.sup.2, 300 openings/cm.sup.2, 400
openings/cm.sup.2, 500 openings/cm.sup.2, 600 openings/cm.sup.2,
700 openings/cm.sup.2, 750 openings/cm.sup.2, 800
openings/cm.sup.2, 900 openings/cm.sup.2, 1000 openings/cm.sup.2,
2000 openings/cm.sup.2, 3000 openings/cm.sup.2, or even least 4000
openings/cm.sup.2; in some embodiments, in a range from 30
openings/cm.sup.2 to 200 openings/cm.sup.2, 200 openings/cm.sup.2
to 500 openings/cm.sup.2, or even 500 openings/cm.sup.2 to 4000
openings/cm.sup.2), wherein the openings each have a series of
areas through the openings from the first and second major surfaces
ranging from minimum to maximum areas, wherein the minimum area is
not at at least one of the major surfaces, wherein the polymeric
layer is immiscible with the pressure sensitive adhesive, and
wherein the strippable layer is removable from the layer comprising
pressure sensitive adhesive at a peel force less than 200 grams per
cm (in some embodiments, less than 150 grams per cm, 100 grams per
cm, 50 grams per cm, or even less than 20 grams per cm) as
determined by the Peel Test described in the Examples.
[0020] In another aspect, the present disclosure provides a method
of making the second polymeric multilayer film, the method
comprising:
[0021] extruding at least the backing layer comprising the first
thermoplastic polymer, the layer comprising pressure sensitive
adhesive, optionally the tie layer, and the strippable layer
comprising the second thermoplastic polymer into a nip to provide a
polymeric multilayer film, wherein the nip comprises a first roll
having a structured surface that imparts indentations through a
first major surface of the polymeric multilayer film; and
[0022] passing the first major surface having the indentations over
a chill roll while applying a heat source to a generally opposed
second major surface of the polymeric multilayer film, wherein the
application of heat from the heat source results in formation of
openings to provide the polymeric multilayer film. In some
embodiments, the strippable layer is separated from the other
extruded layers, including in some embodiments, removing the
strippable layer before passing the first major surface having the
indentations over the chill roll.
[0023] Polymeric multilayer films described herein are useful, for
example, for medical dressings, or as graphics films.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1A shows an intermediate of one exemplary polymeric
multilayer film described herein.
[0025] FIG. 1B shows one exemplary polymeric multilayer film
described herein.
[0026] FIG. 1C shows an exemplary apparatus for making the
polymeric multilayer film shown in FIG. 1B.
[0027] FIG. 2A shows another intermediate exemplary polymeric
multilayer film described herein.
[0028] FIG. 2B shows another exemplary polymeric multilayer film
described herein.
[0029] FIG. 2C shows an exemplary apparatus for making the
polymeric multilayer film shown in FIG. 2B.
DETAILED DESCRIPTION
[0030] Referring to FIG. 1A, exemplary polymeric multilayer film
100 has first and second generally opposed major surfaces 102, 103.
Polymeric multilayer film 100 has liner layer 110, pressure
sensitive adhesive 112, optional tie layer 114, and layer
comprising a thermoplastic polymer 116. Array of indentations 118
extends from first major surface 101 of polymeric multilayer film
100, wherein there are at least 30 indentations/cm.sup.2.
Optionally indentations 118 leave a thickness t.sub.1 of material
119 comprising at least one of layers 112, 114 and 116, of less
than 25 micrometers.
[0031] Referring to FIG. 1B, exemplary polymeric multilayer film
101 has first and second generally opposed major surfaces 102, 104.
Polymeric multilayer film 101 has layer comprising pressure
sensitive adhesive 112, and optional tie layer 114, and layer
comprising a thermoplastic polymer 116. Array of openings 120
extends between first and second major surfaces 102, 104 of
polymeric multilayer film 101, wherein there are at least 30
openings/cm.sup.2. Openings 120 each have a series of areas through
the openings from first and second major surfaces 102, 104 ranging
from minimum to maximum areas 121, 122, respectively. Minimum area
121 is not at at least one of first or second major surfaces 102,
104. Polymeric multilayer film 101 thickness t2 is greater than 50
micrometers.
[0032] Referring to FIG. 1C, exemplary apparatus 140 for making
polymeric multilayer film 101. At least two layers 112, 116 are
extruded through die 142 into nip 144 at the same time as liner
layer 110 is fed into nip 144 to provide polymeric film 100 with
liner layer 110. Nip 144 comprises first roll 146 having structured
surface 147 that imparts indentations 118 extending into at least
first and second layers 112, 116 and providing polymeric multilayer
film 100. The liner layer 110 is then removed from the extruded
layers and the first major surface 102 having indentations 118 is
passed over chill roll 150 while applying heat 152 from heat source
154 to the second major surface 104 of polymeric film 101.
Application of heat 152 results in the formation of an array of
openings 120 extending between first and second major surfaces 102,
104 of polymeric film 101.
[0033] Materials for making an apparatus for making polymeric
multilayer films described herein include those known in the art
for multilayer film making apparatuses, as well as materials used
in the Examples, and/or materials apparent to those skilled in the
art after reviewing the instant disclosure. For example, the rolls
can be made of metals such as steel. In some embodiments, the
surface of rolls contacting the polymeric material(s) are chrome
plated, copper plated, or are aluminum. Rolls can be chilled, for
example, using conventional techniques such as water cooling. Nip
force can be provided, for example, by pneumatic cylinders.
[0034] In some embodiments, extrusion speeds include those in a
range from 3-15 m/min. (in some embodiments, in a range from 15 to
50 m/min., 50 to 100 m/min., or more). In some embodiments,
extrusion temperatures are in range from 200.degree. C. to
230.degree. C. (in some embodiments, in a range from 230.degree. C.
to 260.degree. C., 260.degree. C. to 300.degree. C., or
greater).
[0035] Referring to FIG. 2A, exemplary polymeric multilayer film
200 has first and second generally opposed major surfaces 202, 203.
Polymeric multilayer film 200 has backing layer 202 comprising a
first thermoplastic polymer, optional tie layer 214, layer
comprising a pressure sensitive adhesive 212, and strippable layer
comprising a second thermoplastic polymer 210. Layer 210 is
immiscible with pressure sensitive adhesive 212. Strippable layer
210 is removable from pressure sensitive adhesive layer 212 at a
peel force less than 200 grams per cm (in some embodiments, less
than 150 grams per cm, 100 grams per cm, 50 grams per cm, or even
less than 20 grams per cm) as determined by the Peel Test described
in the Examples. Array of indentations 218 extend from first major
surface 202 of polymeric multilayer film 200, wherein there are at
least 30 indentations/cm.sup.2. Optionally, indentations 218 leave
a thickness t3 of material 219 comprising at least one of layers
112, 114, and 116, of less than 25 micrometers.
[0036] Referring to FIG. 2B, exemplary polymeric multilayer film
101 has first and second generally opposed major surfaces 202, 204.
Polymeric multilayer film 201 has layer 216 comprising a first
thermoplastic polymer, optional tie layer 214, and layer comprising
a pressure sensitive adhesive 212. Array of openings 220 extends
between first and second major surfaces 202, 204 of polymeric
multilayer film 201, wherein there are at least 30
openings/cm.sup.2. Openings 220 each have a series of areas through
the openings from first and second major surfaces 102, 104 ranging
from minimum to maximum areas 221, 222, respectively. Minimum area
221 is not at at least one of first or second major surfaces 202,
204. Polymeric multilayer film 201 thickness t4 is greater than 50
micrometers.
[0037] Referring to FIG. 2C, exemplary apparatus 240 for making
polymeric multilayer film 201. At least two layers 212, 216 are
extruded through die 242 into nip 244 to provide polymeric film
200. Nip 244 comprises first roll 246 having structured surface 247
that imparts indentations 218 extending into at least first and
second layers 212, 216, and providing polymeric multilayer film
200. The strippable layer 210 is then removed from the extruded
layers and the first major surface 202 having indentations 218 is
passed over chill roll 250 while applying heat 252 from heat source
254 to the second major surface 204 of polymeric film 201.
Application of heat 252 results in the formation of an array of
openings 220 extending between first and second major surfaces 202,
204 of polymeric film 201.
[0038] Exemplary pressure sensitive adhesive (PSA) includes
tackified natural rubbers, synthetic rubbers, tackified styrene
block copolymers, polyvinyl ethers, acrylics, poly-a-olefins, and
silicones, and acrylate-based PSA's (including those described, for
example, in U.S. Pat. No. 4,181,752 (Clemens et al.) and U.S. Pat.
No. 4,418,120 (Kealy et al.), PCT Pub. No. WO 95/13331, and in
Handbook of Pressure-Sensitive Adhesives Technology, Ed. D. Satas,
2nd Edition, Von Nostrand Reinhold, New York, 1989).
[0039] Exemplary tie layer materials include ethylene methyl
acrylate (EMA) copolymers, ethylene acrylic acid (EAA) copolymers,
ethylene butyl acrylate (EBA) copolymers, ethylene vinyl acetate
(EVA), ethylene acid terpolymers, polybutene (PB), and
polymethylpentenes (PMP). As is understood by one skilled in the
art, a suitable tie layer material is chosen to aid in bonding the
chosen thermoplastic polymer layer and pressure sensitive adhesive
together.
[0040] Exemplary thermoplastic polymers for the backing layer
include polyamide 6, polyamide 66, polyethyleneterephthalate (PET),
copolyester (PETg), cellulose acetobutyrate (CAB), 30
polymethylmethacrylate (PMMA), acrylonitrile butadiene styrene
(ABS), polyolefin copolymers, polyethylene, polystyrene (PS),
ethylene vinyl alcohol (EVOH), polycarbonate (PC),
polybutyleneterephthalate (PBT), polyethylenenaphthalate (PEN), and
polypropylene.
[0041] Exemplary thermoplastic polymers for the strippable layer
include at least one olefinic block copolymers. Exemplary
alpha-olefins include at least one of butene-1 alpha-olefin, a
hexene-1 alpha-olefin, or octene-1 alpha-olefin. Generally,
copolymers of ethylene and octene-1 are used as release layers, for
example, with acrylate-based pressure sensitive adhesives. The
copolymers are generically described as olefinic block copolymers.
Typically, the copolymers have a density up to 0.90 g/cm.sup.3 (in
some embodiments, up to 0.89 g/cm.sup.3, or even up to 0.88
g/cm.sup.3; in some embodiments, in a range from 0.85 g/cm.sup.3 to
0.90 g/cm.sup.3, 0.85 g/cm.sup.3 to 0.89 g/cm.sup.3, or even 0.85
g/cm.sup.3 to 0.88 g/cm.sup.3). In some embodiments, the copolymers
may be blended with other olefinic polymers (e.g., polyethylene) to
increase the elastic modulus of the strippable layer in order to
reduce elongation of the layer during removal of the layer from the
film. Exemplary polyethylenes include low density polyethylene
(LDPE) (i.e., in a range from 0.910 g/cm.sup.3 to 0.925
g/cm.sup.3), medium density polyethylene (MDPE) (i.e., in a range
from 0.926 g/cm.sup.3 to 0.940 g/cm.sup.3), and high density
polyethylene (HDPE) (i.e., at least 0.941 g/cm.sup.3). In some
embodiments, the percentage of added polyethylene, by mass, is up
to 10% (in some embodiments, up to 20%, 30%, 40%, or even up to
50%).
[0042] In some embodiments, at least one layer of a polymeric
multilayer films described herein may include an additive such as
inorganic fillers, pigments, slip agents, and flame retardants.
Such additives are known in the art and used in some polymeric
multilayer films.
[0043] The liner layer can be made, for example, from polyethylene
terephthalate (PET), polyethylene napthalate (PEN), polycarbonate
or other suitable polymers.
[0044] In some embodiments, polymeric multilayer films described
herein have a thickness greater than 50 micrometers (in some
embodiments, greater than 75 micrometers, 100 micrometers, 125
micrometers, 150 micrometers, 200 micrometers, 250 micrometers, 500
micrometers, 750 micrometers, 1000 micrometers, 1500 micrometers,
2000 micrometers, or even at least 2500 micrometers; in some
embodiments, in a range from 50 micrometers to 1500 micrometers,
125 micrometers to 1500 micrometers, or even 125 micrometers to
2500 micrometers).
[0045] In some embodiments, polymeric multilayer films described
herein have at least 50 openings/cm.sup.2 (in some embodiments, 75
openings/cm.sup.2, 100 openings/cm.sup.2, 200 openings/cm.sup.2,
250 openings/cm.sup.2, 300 openings/cm.sup.2, 400
openings/cm.sup.2, 500 openings/cm.sup.2, 600 openings/cm.sup.2,
700 openings/cm.sup.2, 750 openings/cm.sup.2, 800
openings/cm.sup.2, 900 openings/cm.sup.2, 1000 openings/cm.sup.2,
2000 openings/cm.sup.2, 3000 openings/cm.sup.2, or even least 4000
openings/cm.sup.2; in some embodiments, in a range from 30
openings/cm.sup.2 to 200 openings/cm.sup.2, 200 openings/cm.sup.2
to 500 openings/cm.sup.2, or even 500 openings/cm.sup.2 to 4000
openings/cm.sup.2).
[0046] In some embodiments, the openings have a largest dimension
of at least 50 micrometers (in some embodiments, at least 75
micrometers, 100 micrometers, 125 micrometers, 150 micrometers, 250
micrometers, 500 micrometers, or 1000 micrometers; in some
embodiments, in a range from 50 micrometers to 100 micrometers, 50
micrometers to 150 micrometers, 50 micrometers, to 250 micrometers,
100 micrometers to 250 micrometers, 250 micrometers to 500
micrometers, 500 micrometers to 1000 micrometers, 50 micrometers to
1000 micrometers, or even 100 micrometers to 1000 micrometers).
[0047] Polymeric multilayer films described herein are useful, for
example, for medical tapes and dressings.
Exemplary Embodiments
[0048] 1A. A polymeric multilayer film having first and second
generally opposed major surfaces, the polymeric film comprising in
order:
[0049] a layer comprising a pressure sensitive adhesive,
[0050] optionally a tie layer, and
[0051] a layer comprising a thermoplastic polymer,
an array of openings extending between the first and second major
surfaces, and a thickness greater than 50 micrometers (in some
embodiments, greater than 75 micrometers, 100 micrometers, 125
micrometers, 150 micrometers, 200 micrometers, 250 micrometers, 500
micrometers, 750 micrometers, 1000 micrometers, 1500 micrometers,
2000 micrometers, or even at least 2500 micrometers; in some
embodiments, in a range from 50 micrometers to 1500 micrometers,
125 micrometers to 1500 micrometers, or even 125 micrometers to
2500 micrometers), wherein there are at least 30 openings/cm.sup.2
(in some embodiments, at least 50 openings/cm.sup.2, 75
openings/cm.sup.2, 100 openings/cm.sup.2, 200 openings/cm.sup.2,
250 openings/cm.sup.2, 300 openings/cm.sup.2, 400
openings/cm.sup.2, 500 openings/cm.sup.2, 600 openings/cm.sup.2,
700 openings/cm.sup.2, 750 openings/cm.sup.2, 800
openings/cm.sup.2, 900 openings/cm.sup.2, 1000 openings/cm.sup.2,
2000 openings/cm.sup.2, 3000 openings/cm.sup.2, or even least 4000
openings/cm.sup.2; in some embodiments, in a range from 30
openings/cm.sup.2 to 200 openings/cm.sup.2, 200 openings/cm.sup.2
to 500 openings/cm.sup.2, or even 500 openings/cm.sup.2 to 4000
openings/cm.sup.2), wherein the openings each have a series of
areas through the openings from the first and second major surfaces
ranging from minimum to maximum areas, and wherein the minimum area
is not at at least one of the major surfaces. 2A. The polymeric
multilayer film of Exemplary Embodiment 1A, wherein the openings
have a largest dimension of at least 50 micrometers (in some
embodiments, at least 75 micrometers, 100 micrometers, 125
micrometers, 150 micrometers, 250 micrometers, 500 micrometers, or
1000 micrometers; in some embodiments, in a range from 50
micrometers to 100 micrometers, 50 micrometers to 150 micrometers,
50 micrometers, to 250 micrometers, 100 micrometers to 250
micrometers, 250 micrometers to 500 micrometers, 500 micrometers to
1000 micrometers, 50 micrometers to 1000 micrometers, or even 100
micrometers to 1000 micrometers). 3A. The polymeric multilayer film
of any preceding A Exemplary Embodiment, wherein the tie layer
comprises at least one of an ethylene methyl acrylate (EMA)
copolymer, ethylene acrylic acid (EAA) copolymer, ethylene butyl
acrylate (EBA) copolymer, ethylene vinyl acetate (EVA), ethylene
acid terpolymer, polybutene (PB), or polymethylpentene (PMP). 4A.
The polymeric multilayer film of any preceding A Exemplary
Embodiment, wherein the pressure sensitive adhesive comprises at
least one of a natural rubber, a synthetic rubber, a styrene block
copolymer, a polyvinyl ether, an acrylic, a poly-a-olefin, a
silicone, or an acrylate. 5A. The polymeric multilayer film of any
preceding A Exemplary Embodiment, wherein the thermoplastic polymer
is at least one of polyamide 6, polyamide 66,
polyethyleneterephthalate (PET), copolyester (PETg), cellulose
acetobutyrate (CAB), 30 polymethylmethacrylate (PMMA),
acrylonitrile butadiene styrene (ABS), polyolefin copolymers,
polyethylene, polystyrene (PS), ethylene vinyl alcohol (EVOH),
polycarbonate (PC), polybutyleneterephthalate (PBT),
polyethylenenaphthalate (PEN), or polypropylene. 6A. An article
comprising the polymeric multilayer film of any preceding A
Exemplary Embodiment and a liner layer adjacent the layer
comprising pressure sensitive adhesive, such that the order of the
layer is:
[0052] the liner layer,
[0053] the layer comprising pressure sensitive adhesive,
[0054] optionally the tie layer, and
[0055] the layer comprising thermoplastic polymer.
7A. The polymeric multilayer film of any preceding A Exemplary
Embodiment, wherein the liner layer comprises at least one of
polyethylene terephthalate (PET), polyethylene napthalate (PEN), or
polycarbonate. 1B. A method of making a polymeric multilayer film,
the method comprising:
[0056] extruding at least the layer comprising pressure sensitive
adhesive, optionally the tie layer, and the layer comprising
thermoplastic polymer into a nip along with a liner layer to
provide a polymeric multilayer film with a liner layer, wherein the
nip comprises a first roll having a structured surface that imparts
indentations through a first major surface of the polymeric
multilayer film;
[0057] removing the liner; and
[0058] passing the first major surface having the indentations over
a chill roll while applying a heat source to a generally opposed
second major surface of the polymeric multilayer film, wherein the
application of heat from the heat source results in formation of
openings to provide the polymeric multilayer film of either
Exemplary Embodiment 6A or 7A.
1C. A polymeric multilayer film having first and second generally
opposed major surfaces, the polymeric film comprising in order:
[0059] a backing layer comprising a first thermoplastic
polymer,
[0060] a layer comprising a pressure sensitive adhesive,
[0061] optionally a tie layer, and
[0062] a strippable layer comprising a second (in some embodiments,
different) thermoplastic polymer,
an array of openings extending between the first and second major
surfaces, and a thickness greater than 50 micrometers (in some
embodiments, greater than 75 micrometers, 100 micrometers, 125
micrometers, 150 micrometers, 200 micrometers, 250 micrometers, 500
micrometers, 750 micrometers, 1000 micrometers, 1500 micrometers,
2000 micrometers, or even at least 2500 micrometers; in some
embodiments, in a range from 50 micrometers to 1500 micrometers,
125 micrometers to 1500 micrometers, or even 125 micrometers to
2500 micrometers), wherein there are at least 30 openings/cm.sup.2
(in some embodiments, at least 50 openings/cm.sup.2, 75
openings/cm.sup.2, 100 openings/cm.sup.2, 200 openings/cm.sup.2,
250 openings/cm.sup.2, 300 openings/cm.sup.2, 400
openings/cm.sup.2, 500 openings/cm.sup.2, 600 openings/cm.sup.2,
700 openings/cm.sup.2, 750 openings/cm.sup.2, 800
openings/cm.sup.2, 900 openings/cm.sup.2, 1000 openings/cm.sup.2,
2000 openings/cm.sup.2, 3000 openings/cm.sup.2, or even least 4000
openings/cm.sup.2; in some embodiments, in a range from 30
openings/cm.sup.2 to 200 openings/cm.sup.2, 200 openings/cm.sup.2
to 500 openings/cm.sup.2, or even 500 openings/cm.sup.2 to 4000
openings/cm.sup.2), wherein the openings each have a series of
areas through the openings from the first and second major surfaces
ranging from minimum to maximum areas, wherein the minimum area is
not at at least one of the major surfaces, wherein the polymeric
layer is immiscible with the pressure sensitive adhesive, and
wherein the strippable layer is removable from the layer comprising
pressure sensitive adhesive at a peel force less than 100 grams per
cm (in some embodiments, less than 50 grams per cm, or even less
than 20 grams per cm) as determined by the Peel Test described in
the Examples. 2C. The polymeric multilayer film of Exemplary
Embodiment 1C, wherein the openings have a largest dimension of at
least 50 micrometers (in some embodiments, at least 75 micrometers,
100 micrometers, 125 micrometers, 150 micrometers, 250 micrometers,
500 micrometers, or 1000 micrometers; in some embodiments, in a
range from 50 micrometers to 100 micrometers, 50 micrometers to 150
micrometers, 50 micrometers, to 250 micrometers, 100 micrometers to
250 micrometers, 250 micrometers to 500 micrometers, 500
micrometers to 1000 micrometers, 50 micrometers to 1000
micrometers, or even 100 micrometers to 1000 micrometers). 3C. The
polymeric multilayer film of any preceding C Exemplary Embodiment,
wherein the tie layer comprises at least one of an ethylene methyl
acrylate (EMA) copolymer, ethylene acrylic acid (EAA) copolymer,
ethylene butyl acrylate (EBA) copolymer, ethylene vinyl acetate
(EVA), ethylene acid terpolymer, polybutene (PB), or
polymethylpentene (PMP). 4C. The polymeric multilayer film of any
preceding C Exemplary Embodiment, wherein the pressure sensitive
adhesive comprises at least one of a natural rubber, a synthetic
rubber, a styrene block copolymer, a polyvinyl ether, an acrylic, a
poly-a-olefin, a silicone, or an acrylate. 5C. The polymeric
multilayer film of any preceding C Exemplary Embodiment, wherein
the thermoplastic polymer is at least one of polyamide 6, polyamide
66, polyethyleneterephthalate (PET), copolyester (PETg), cellulose
acetobutyrate (CAB), 30 polymethylmethacrylate (PMMA),
acrylonitrile butadiene styrene (ABS), polyolefin copolymers,
polyethylene, and polystyrene (PS), ethylene vinyl alcohol (EVOH),
polycarbonate (PC), polybutyleneterephthalate (PBT),
polyethylenenaphthalate (PEN), or polypropylene. 1D. A method of
making a polymeric multilayer film, the method comprising:
[0063] extruding at least the backing layer comprising the first
thermoplastic polymer, the layer comprising pressure sensitive
adhesive, optionally the tie layer, and the strippable layer
comprising the second thermoplastic polymer into a nip to provide a
polymeric multilayer film, wherein the nip comprises a first roll
having a structured surface that imparts indentations through a
first major surface of the polymeric multilayer film; and
[0064] passing the first major surface having the indentations over
a chill roll while applying a heat source to a generally opposed
second major surface of the polymeric multilayer film, wherein the
application of heat from the heat source results in formation of
openings to provide the polymeric multilayer film of any of
Exemplary Embodiments 1C to 5C.
2D. The method of Exemplary Embodiment 1D further comprising
removing the strippable layer from the other extruded layers. 3D.
The method of Exemplary Embodiment 2D further comprising removing
the strippable layer from the other extruded layers before passing
the first major surface having the indentations, over the chill
roll. 4D. The polymeric multilayer film of any preceding D
Exemplary Embodiment, wherein the strippable layer comprises at
least one of a butene-1 alpha-olefin, a hexene-1 alpha-olefin, or
octene-1 alpha-olefin. 5D. The polymeric multilayer film of
Exemplary Embodiment 4D, further comprising a polyethylene.
[0065] Advantages and embodiments of this invention are further
illustrated by the following examples, but the particular materials
and amounts thereof recited in these examples, as well as other
conditions and details, should not be construed to unduly limit
this invention. All parts and percentages are by weight unless
otherwise indicated.
Peel Test
[0066] The peel force between two layers of a polymeric multilayer
film was determined as follows. A strip about 2.54 cm wide and at
least 30 cm long was cut from the film. The strip was applied to a
rigid plate that was fixed to the flat test bed of a testing
machine (obtained under the trade designation "IMASS MODEL SP2000"
from IMass Inc., Accord, Mass.), using double-sided tape (obtained
under the trade designation "LSE300" from 3M, Maplewood Minn.),
with the adhesive tape applied to the surface of the film that was
contacting the structured roll in the nip. The leading edge of the
strippable layer or liner was then separated from the film and
clamped to a fixture connected to the peel-tester load-cell. The
platen holding the plate/test-strip assembly was then carried away
from the load-cell at constant speed of about 228 cm/minute (90
inches/minute), effectively peeling the strippable skin layer from
the film at about a 180 degree angle. As the platen moves away from
the clamp, the force required to peel the strippable skin layer off
the film was sensed by the load cell and recorded by a
microprocessor. The force required for peel was then averaged over
5 seconds of steady-state travel and recorded. There was a delay of
1 second from the start of the movement of the platen before
recording the 5 seconds of data in order to remove any initial high
force values generated at the start of the peel.
Example 1
[0067] Referring to FIGS. 1A, 1B, and 1C, a perforated multilayer
polymeric film (101) was prepared as follows. A three layer
polymeric film consisting of layers A, B, and C (ABC) was prepared
using three extruders to feed a 25 cm wide, 3 layer multi-manifold
die (142) (obtained under the trade designation "CLOEREN" from
Cloeren Inc., Orange, Tex.). The extrusion process was done
horizontally into a nip (144) with a tooling roll (146) and backup
roll (145). The extrusion process was configured such that layer A
contacted the tooling roll (146) and layer C contacted the backup
roll (145), as shown in FIG. 1C. The polymer for layer A was
provided with a 6.35 cm single screw extruder. The polymer for
layer B was provided with a 208 liter (55 gallon) adhesive drum
unloader and 5 cm.sup.3 size gear pump. The polymer for layer C was
provided with a 3.2 cm single screw extruder. Heating zone
temperatures for the extruders drum unloader, and die, and the rpms
for the extruders are shown in Table 1, below.
TABLE-US-00001 TABLE 1 6.35 cm 3.2 cm (2.5 inch) Drum Unloader
(1.25 inch) Die, Heating Zones Layer A, .degree. C. Layer B,
.degree. C. Layer C, .degree. C. .degree. C. Zone 1 193 204 191 210
Zone 2 204 204 204 210 Zone 3 210 N/A 210 210 Zone 4 210 N/A N/A
N/A End cap 210 N/A 210 N/A Neck Tube 210 210 210 N/A Platen N/A
210 N/A N/A Manifold N/A 210 N/A N/A
[0068] The rpms of the extruders are listed in Table 2, below.
TABLE-US-00002 TABLE 2 6.35 cm 3.2 cm (2.5 inch) Gear Pump (1.25
inch) Layer A Layer B Layer C Rpm 18 2.8 20
[0069] Referring to FIGS. 2A, 2B, and 2C, layer A (216) was
extruded using polypropylene/polyethylene impact copolymer (35 melt
flow rate; obtained under the trade designation "DOW C700 35N" from
Braskem PP Americas, Philadelphia, Pa.). Layer B (212) was extruded
using pressure sensitive adhesive, a 50:50 by weight mixture of
styrene-isoprene-styrene block copolymer (obtained under the trade
designation "KRATON 1161" from Kraton Performance Polymers Co.,
Houston, Tex.) and tackifying resin (obtained under the trade
designation "WINGTACK+" from Total Petrochemicals USA, Inc., Port
Arthur, Tex.). Layer C (210) was extruded using olefin block
copolymer resin (obtained under the trade designation "INFUSE 9507"
from Dow Chemical Company, Midland, Mich.).
[0070] The two rolls providing the nip were water cooled rolls
(245, 246) with face widths of 30.5 cm. The tooling roll (246)
having a nominal diameter of 30.5 cm. The backup roll (245) having
a nominal diameter of 31.6 cm, including a 1.3 cm thick outer
covering of an 85 Shore A durometer silicone rubber. The tooling
roll (246) had a temperature setpoint of 46.degree. C. and the
backup roll (245) had a temperature set point of 16.degree. C. The
tooling roll (246) had male post features (247) cut into the
surface of the roll. The male post features were chrome plated. The
male features (defined as posts) (247) on the tool surface were
flat square topped pyramids with a square base. The top of the
posts were 102 micrometers square and the bases were 293
micrometers square. The overall post height was 432 micrometers.
The center to center spacing of the posts was 1834 micrometers in
both the radial and cross roll directions. The backup roll (245)
had a temperature set point of 38.degree. C. The tooling roll (246)
and backup roll (245) were directly driven. The nip force between
the two nip rolls was 117 Newtons per linear centimeter. The
extrudate takeaway line speed was 7.6 m/min.
[0071] The polymers for the three layers were extruded from the die
(242) directly into the nip (244) between the tooling (246) and
backup roll (245). The male features (247) on the tooling roll
(246) created indentations (218) in the extrudate. A thin layer of
polymer (219) remained between the tooling (246) and backup roll
(245). Typically this layer (219) was less than 20 micrometer
thick. The extrudate remained on the tooling roll (246) for 180
degrees of wrap to chill and solidify the extrudate into a
multi-layer polymeric film. The multi-layer film was then wound
into roll form.
[0072] The multi-layer polymeric film was then converted into a
perforated film as follows. The film was passed under a
methylacetylene-propadiene propane flame from a handheld torch at a
speed of about 7.6 m/min, at a distance of about 5.0 cm with the
membrane towards the flame. The resulting film contained
perforations of about 147 micrometers diameter. Layer C was then
removed from the film with the peel test measuring the force as 87
g/cm.
Example 2
[0073] Example 2 was prepared as described for Example 1, except
that prior to converting into a perforated film, Layer C was
removed from the film. The peel test measured the peel force of
removing Layer C as 81 g/cm. The resulting film contained
perforations of about 95 micrometers diameter.
Example 3
[0074] Example 3 was prepared as described for Example 1, except
that Layer C was not extruded through the die, so that only Layers
A and B were extruded into the nip. In addition, a polyethylene
terephthalate (PET) liner (110) 0.05 mm thick with silicone release
coating applied to one side was introduced into the nip (144) by
wrapping 90 degrees around the nip roll with the release coating
side contacting Layer B upon entering the nip.
[0075] The multilayer polymeric film was then converted into a
perforated film as in Example 2, except that the PET liner layer
(110) was removed from the film prior to creating the perforations
as in Example 1. The resulting film contained perforations of about
152 micrometers diameter. The peel test measured the peel force of
removing the liner layer (110) as 34 g/cm.
[0076] Foreseeable modifications and alterations of this disclosure
will be apparent to those skilled in the art without departing from
the scope and spirit of this invention. This invention should not
be restricted to the embodiments that are set forth in this
application for illustrative purposes.
* * * * *